Two weeks ago, America relinquished the lead role in Operation Odyssey Dawn to NATO. The U.S., which led the operation’s initial decapitation phase to protect the Libyan people against systematic attacks, has more pressing priorities in East Asia and the Middle East. Besides, Libya is a European concern, not an American problem.

NATO’s performance hasn’t been impressive. The alliance’s mission conduct is marked by incompatible goals and political and operational infighting, and most members are too stingy with their militaries. The unintended consequence is to encourage Libyan dictator Muammar Gaddafi, who is playing NATO’s fecklessness for a stalemate.

U.S. Adm. James Stavridis, the senior NATO military commander, said the alliance needs to increase its arsenal of sophisticated aircraft capable of launching precise attacks. Only 14 of the alliance’s 28 members are actively participating in the operation, and just six of those are striking targets on the ground in Libya. Meanwhile, the U.S. supports the operation with 46 aircraft for command-and-control, electronic warfare, and refueling missions, which accounts for half of the operation’s overall costs.

NATO’s lackluster performance in Libya demonstrates that the alliance has outlived its usefulness. Consider five more reasons America should quit the alliance.

First, America pays disproportionately for Europe’s security, while the Europeans are on a defense-spending holiday. The U.S. contributes 25% of NATO’s operating budget and spends more than twice the percentage of its gross domestic product on defense [4.7%], compared with all but one of its NATO partners [Greece at 4%]. Economic powers France and Germany do not reach NATO’s 2% threshold for security spending.

The majority of NATO-related expenses are incurred by members from the deployment of their armed forces. Not surprisingly, the U.S. leads NATO deployment expenditures because it has the largest and only expeditionary force.

NATO also relies on America’s strategic umbrella — its nuclear arsenal with help from Great Britain and France. But NATO partners such as Germany pay nothing for this strategic umbrella. In fact, Berlin doesn’t even intend to invest in new aircraft that have the capability to deliver atomic weapons, a change from the Cold War era.

Second, the lack of defense investment results in ill-prepared NATO militaries. Most NATO forces lack sufficient helicopters and unmanned aerial vehicles for operations in Afghanistan, and few European troops are equipped and trained for modern warfare. Only a couple European partners have an expeditionary capability to deploy even 30% of their forces, and only Great Britain approaches true combat interoperability with U.S. forces. Interoperability is critical to coalition operations.

Third, NATO is irrelevant when dealing with modern security threats. The alliance lacks fundamental technologies for fighting terrorism, rebuilding failed states, and fighting counterinsurgencies. These deficiencies are significant given that Europe’s backyard is becoming a less predictable and a more perilous place conducive to asymmetric threats, rogue states with weapons of mass destruction such as Iran, threats to global supply lines, and cyber attacks on critical infrastructure.

Fourth, NATO is not a promising global partner. NATO Secretary General Anders Fogh Rasmussen doesn’t intend for the alliance to become a tool of America’s global role, which raises the question of its relevance for America’s long-term security interests.

Afghanistan has become a crucible for the alliance’s global partnering, and this isn’t working out. America had to drag NATO into the Afghanistan war, which exposed the alliance’s “two-tiered” nature, according to U.S. Defense Secretary Robert Gates. The secretary said, "You have some allies willing to fight and die to protect people’s security, and others who are not. It puts a cloud over the future of the alliance if this is to endure and perhaps get even worse.”

Specifically, Gates is frustrated with NATO’s reluctance to put forces in harm’s way in Afghanistan. Most of the NATO nations contributing troops impose caveats that dictate strict rules of engagement, which severely limits their usefulness. That puts a heavy burden on the few nations such as the U.S. willing to fight.

Finally, Europe is no longer key to American security because the Soviet Union, our Cold War nemesis, is gone, and in its place is the Russian Federation, which poses far less of a strategic threat. That is why the U.S. is shifting its resources from Europe to the Middle East and Asia. Therefore a European-based alliance with no interest in other regions has a diminishing interest for Washington.

Last week, Gates warned that the U.S. military would have to scale back its overseas commitments and shrink to meet President Barack Obama’s proposed defense cuts. That is why America’s remaining European-based forces and investments in NATO’s budget and operations should be high on Gates’ list of potential defense cuts.

These issues justify Washington’s reconsideration of our NATO membership. If NATO does not transform into a multilateral security alliance that addresses 21st century challenges with a global expeditionary capability, the U.S. should quit.

Elizabeth Sherwood Randall, director for European affairs at the U.S. National Security Council, suggests NATO needs to reform to be remain relevant. She said, "While allied leaders haggle over commitments to the fight in Afghanistan [and elsewhere], NATO needs to keep its eyes on the strategic prize: an alliance that can thrive in an increasingly messy world.”

The best way for NATO to thrive in this “messy world” is to become a multilateral alliance with a portfolio that includes missile defense against Iran, cyber security, nation-building in failed states, and much more. Alternatively, the U.S. should invest in partners willing to play a global role, and develop these partnerships with countries such as India, Brazil, and Australia, and the few Europeans with credible military capabilities and global willingness.

NATO either develops a credible 21st century global capability and the willingness to fight for mutual security interests, or the U.S. should prioritize Europe below other regions by quitting NATO and investing our dwindling defense dollars in willing partners.